The state of cell block variation and satisfaction in the era of molecular diagnostics and personalized medicine

Abstract

Background:In the recent past, algorithms and recommendations to standardize the morphological, immunohistochemical and molecular classification of lung cancers on cytology specimens have been proposed, and several organizations have recommended cell blocks (CBs) as the preferred modality for molecular testing. Based on the literature, there are several different techniques available for CB preparation-suggesting that there is no standard. The aim of this study was to conduct a survey of CB preparation techniques utilized in various practice settings and analyze current issues, if any.Materials and Methods:A single E-mail with a link to an electronic survey was distributed to members of the American Society of Cytopathology and other pathologists. Questions pertaining to the participants’ practice setting and CBs-volume, method, quality and satisfaction-were included.Results:Of 95 respondents, 90/95 (94%) completed the survey and comprise the study group. Most participants practice in a community hospital/private practice (44%) or academic center (41%). On average, 14 CBs (range 0-50; median 10) are prepared by a laboratory daily. Over 10 methods are utilized: Plasma thrombin (33%), HistoGel (27%), Cellient automated cell block system (8%) and others (31%) respectively. Forty of 90 (44%) respondents are either unsatisfied or sometimes satisfied with their CB quality, with low-cellular yield being the leading cause of dissatisfaction. There was no statistical significance between the three most common CB preparation methods and satisfaction with quality.Discussion:Many are dissatisfied with their current method of CB preparation, and there is no consistent method to prepare CBs. In today's era of personalized medicine with an increasing array of molecular tests being applied to cytological specimens, there is a need for a standardized protocol for CB optimization to enhance cellularity.

Adequacy of endosonography‐derived samples from peribronchial or periesophageal intrapulmonary lesions for the molecular profiling of lung cancer

“…We always produced smears besides cell blocks, and carefully retrieved and processed tissue cores separately in those cases in which the procedure yielded them. Although the majority of ancillary tests (both immunohistochemistry and molecular assays) have been validated on formalin‐fixed, paraffin‐embedded material, data from the literature suggest that cell blocks are of suboptimal quality in a non‐negligible percentage of cases . The 21% rate of non‐diagnostic paraffin‐embedded, endosonography‐derived material of the present series is in line with data from the literature .…”

Cell Block in Cytological Diagnostics: Review of Preparatory Techniques

“…The idea of triage was postulated already in the 50s by Birge et al [31]; nevertheless, the majority of laboratories employ only limited CB techniques. In the survey of Crapanzano et al [34], over 10 methods were used in the respondents’ institutions most commonly the plasma/thrombin method, the Histogel- and Cellient CB-techniques. The limited satisfaction with CBs due to low cellularity was clearly shown.…”

“…The volume and liquefaction times are standardized according to the quantity of the material and an extra centrifugation is added at the end. The satisfaction in a multicenter survey of the Histogel-method was the lowest due to low cellular yield; nevertheless, cellular preservation and architecture are appreciated [34]. …”

“…De Girolami [32, 33] showed the diagnostic use of the method in the variety of the tissues and organs. Better cellularity, morphology, cell distribution, and bigger pellet size are appreciated by survey respondents [34]. …”

“…The system is costly, but cost-effectiveness is reached by saving preparation time and shortened sample turn time. In addition, enhanced cellular yield is appreciated [34]. …”